Detacher mechanism for milking unit

ABSTRACT

A milking unit detacher mechanism including a main support column and a vertically movable milker support column slidably mounted on the main support column. The milker support column has a horizontally extending retractable milking unit support assembly mounted thereon adapted to support a milker unit on the end thereof when the milker unit is attached to a cow for milking. The milker unit support assembly can be retracted from its extended position underneath the cow to a retracted position adjacent the cow. A flexible retract member is fastened at one end to the milking unit support assembly and at the other end to a retract means for exerting a pulling force on the flexible retract member to thereby cause the milker unit support assembly to be retracted. The retract means includes a power cylinder having a movable piston rod. When the power cylinder is energized in its retract direction, it operates to pull on the flexible retract member and to also engage the milker support column and move it upwardly in a vertical direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a milking unit support and detacher mechanismand more particularly to a mechanism which operates automatically uponcompletion of the milking cycle to cause the milking unit supported onthe mechanism to be retracted from underneath the cow and also raised toa higher position.

2. Description of the Prior Art

Prior mechanisms of the general type known to applicant are shown inU.S. Pat. Nos. 3,246,631, 3,556,053, 3,603,292 and 3,690,300. Inaddition applicants are aware of a detacher mechanism disclosed in U.S.application Ser. No. 468,925, filed May 10, 1974, which application hasbeen assigned to the assignee of the present application. The principalproblems in the prior art mechanisms referred to above is the relativecomplexity of the mechanisms resulting in generally higher cost and insome instances lower reliability.

SUMMARY OF THE INVENTION

A detacher mechanism for a milking unit comprising a main support columnand a vertically movable milker support column slidably mounted on themain support column. A horizontally extending retractable milking unitsupport assembly is mounted on the movable milker support column. Theretractable support assembly is adapted to support a milker unit on theouter end thereof when the milker unit is attached to a cow for milking.The retractable support assembly is further adapted to be retracted fromits extended position beneath the cow to a retracted position adjacentthe cow at a predetermined point in the milking cycle. A flexibleretract member is fastened at one end to the retractable milking unitsupport assembly and at the other end to the main support column. Aretract means including a power cylinder having a movable piston ismounted on the main support column and is adapted to pull on theflexible retract member to thereby cause the support assembly to beretracted from underneath the cow. The power cylinder is also adaptedwhen energized in its retract direction to engage the movable milkersupport column and move it upwardly in a vertical direction while theretractable support assembly is being retracted from underneath the cow.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary perspective view of a teat cup detachermechanism made in accordance with the present invention;

FIG. 2 is a front elevation view (with parts broken away) of thedetacher mechanism;

FIG. 3 is a side elevation view of the detacher mechanism;

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3; and

FIG. 5 is a partially schematic view of the central means for thedetacher mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1, 2, 3 and 4, the detacher mechanism which isindicated generally by reference numeral 10 is adapted to be used with amilking apparatus 12 of any suitable design. The milking apparatus 12shown in FIG. 1 is comprised of a claw unit 14, a plurality of teat cups16, vacuum lines 18 and a milk line 20.

The detacher mechanism 10 is comprised of two basic sub-assemblies,namely, a vertical column assembly 22 and a horizontally extendingretractable milker unit support assembly 24 mounted at the lower end ofcolumn assembly 22.

Vertical column 22 is comprised of a stationary main support column 26and a vertically adjustable milker support column 28 mounted on column26. Main support column 26 is mounted adjacent a milking stall by anysuitable support structure (not shown) and adjustable column 28 issupported from above on a pulley 30 rotatably mounted on the upper endof support column 26. Column 28 is supported on pulley 30 by a cable 32and a counterweight 34. The vertical movement of column 28 is guided bya pair of guide brackets 36 and 38.

As best shown in FIG. 2, one end of cable 32 is attached to the upperend of column member 28 and the cable is wound around pulley 30 with theother end of the cable being attached to counterweight 34 which in turnis mounted for reciprocal movement inside column 28.

The detacher mechanism is powered by a power cylinder 40 (preferablypneumatic) mounted on main support column 26 by mens of upper and lowerbracket members 36 and 38. Cylinder 40 is of a double-acting type havingan internal piston (not shown) attached to a piston rod 42 and a pair ofair hoses 44 and 46 connected to opposite ends thereof as shown in FIG.2. Cylinder 40 is operatively connected to retractable unit supportassembly 24 by a flexible retract member 48 which in the preferredembodiment is in the form of a ball chain. Chain 48 is wound overpulleys 50 and 52. Pulley 50 is mounted on the end of piston rod 42 by abracket 54 and pulley 52 is mounted on the lower end of column 26 by abracket 56. Chain 48 is fastened at one end to bracket 56 and from thereit extends upwardly to pulley 50 and then around pulley 50 downwardly topulley 52 and then around pulley 52 upwardly to retractable milker unitsupport assembly 24.

As best shown in FIGS. 1 and 4, assembly 24 includes a retractable linkassembly 58 comprised of a plurality of pivotally connected link members60, 62, 64 and 66. The four link members 60, 62, 64 and 66 are pivotallyconnected to each other in end-to-end relationship by suitable pivotpins as shown.

As shown in FIG. 4, the first link member 60 is pivotally mounted on abracket member 68 which in turn is fastened to a second bracket 70 by abolt, nut, friction plate and spring washer assembly 72. Bracket 70 iswelded to short, tubular member 74 which in turn is fastened inside thelower end of column 28 by any suitable means such as a plurality ofmachine screws (not shown). A combination ball chain guide bracket andstop member 76 is also welded to tube 74.

The friction assembly 72 connecting bracket 68 to bracket 70 serves as afriction clutch to permit relative rotation of the two brackets when ashock force is applied to the retractable link assembly 58. Thus shouldsuch a force be applied by a kick from a cow, for example, force will beabsorbed by assembly 72 (causing bracket 68 to be rotated) to therebyprevent damage to the mechanism which might otherwise occur. In suchevent the retractable link assembly 58 can be readily restored to itsproper horizontally extending position by simply gripping the linkassembly and firmly rotating it back to its proper horizontal position.

The retract chain member 48 extending from pulley 52 is threaded throughan opening 78 in bracket 76 and from there it is threaded through anopening 80 in link 62, then through another opening 82 in link 64 andthen fastened to the end link 66. As best shown in FIG. 4, whenretractable link assembly 58 is in its fully retracted position, link 62thereof will abut the face 84 of bracket 76 which serves as a stopmember for the retractable link assembly.

A flexible support 86 in the form of a short length of chain is fastenedto the end of link 66 from which milker unit 12 is supported as shown inFIG. 1. A depending hook member 88 is mounted at the pivot point betweenlinks 64 and 66 which serves to support the vacuum and milk lines 18 and20 as best shown in FIG. 1.

A catch bar member 90 is bolted to the lower end of column 28 by machinescrews 92. The catch bar cooperates with the bracket 54 fastened to theend of piston rod 42 in the retract operation as will be more fullydescribed hereinafter.

As shown in FIG. 5, the detacher mechanism of the present invention iscontrolled by a four-way solenoid valve 94 and a unique milk valve unit96. FIG. 5 shows the four-way solenoid valve in its deenergized positionand the milk valve in its open position.

Milk valve 96 is comprised of fittings 98 and 100 attached to each otherin sealing arrangement by bolts 102 and a gasket 104. Fittings 98 and100 have externally extending tubular portions 106 and 108 forattachment to milk conduits 110 and 112. Fittings 98 and 100 also areprovided with internally extending tubular extensions 114 and 116 whichare adapted for connection to an internal hose member 118 of flexiblematerial such as rubber. Fitting 98 is provided with a jacket portion120 which surrounds the internal rubber hose member 118 to therebyprovide a pressurized chamber 121 around such rubber hose portion. Thejacket is provided with a nipple 122 for connection to an air hose 124as will be described in detail hereinafter. It will be appreciated thatwhen a sufficient pressure differential is created between the inside ofrubber hose element 118 and the chamber 121 around the hose, the hosewill collapse to the position shown in dotted lines to thereby shut offflow between the inlet and outlet of the milk valve 96.

Solenoid valve 94 is shown schematically in FIG. 5 and is comprised of areciprocating valve element 126, a return spring 128 and solenoidactivating coil 130.

OPERATION

To initiate the milking cycle solenoid valve 94 is deenergized whereinit will assume the position shown in FIG. 5. In such condition the topof the cylinder 40 will be pressurized causing piston rod 42 to movedownwardly to the position shown in FIGS. 2 and 3. At the same time thelower end of cylinder 40 and the chamber 121 of milk valve 96 will beconnected to exhaust. This will allow the milk valve to assume its openposition due to the inherent resiliency of tube member 118. With themilk valve in its open position vacuum to the milker unit will besupplied through the milk valve. The milker and detacher apparatus isnow in condition for use.

With the retractable support assembly 24 in retracted position (FIG. 4)the assembly is moved to extended position (FIG. 1) manually by theoperator. At the same time the operator adjusts the vertical position ofassembly 24 by manually raising or lowering column 28 to the properheight for the cow to be milked. It will be appreciated that suchvertical adjustment will cause a movement of counterweight 34 and thatsuch counterweight will keep the column 28 at the desired elevation onceit is set. The operator adjusts the vertical position of assembly 24 toa position wherein the milker unit is completely free floating withrespect to the cow's udder. The flexible support member 86 permits alimited amount of relative movement between the cow and the milker unitwithout disturbing the free floating relationship.

The operator then attaches the teat cups and milking commences and theoperator leaves. Milking continues until the milk flow from the milkerunit 12 drops below a predetermined minimum amount (preferably one-halfpount per minute) at which time a milk flow sensor of any suitabledesign (not shown) will operate to energize solenoid valve 94 as shownin FIG. 5.

Actuation of solenoid valve 94 will cause valve member 126 to move tothe right which in turn will cause air under pressure to be directed tothe bottom of power cylinder 40 through air hose 46 which in turn willcause the piston cylinder and rod 42 thereof to be raised.Simultaneously air under pressure will be directed to chamber 121 ofmilk valve 96 through air line 124 which in turn will cause the milkvalve to close. The closing of the milk valve 96 will turn off thevacuum to the milker unit 12 to thereby facilitate release of the teatcups 16 from the cow.

Initial upward movement of piston rod 42 will produce a retractingmovement of ball chain 48 which in turn will cause the milker unitsupport assembly (and milker unit 12 supported therefrom) to start itsretracting movement from the position shown in FIG. 1 to the positionshown in FIG. 4. In addition, upward movement of the piston rod willcause bracket 54 attached to the end of the piston rod to engage catchbar 90 attached to the end of column 28 which in turn will cause thecolumn to be moved upwardly along with the piston rod.

It will be apparent from the foregoing that in the automatic detachingoperation described above the milker unit 12 is first automaticallyreleased from the cow due to the shut off of vacuum. Immediately,thereafter the milker unit is retracted from underneath the cow by theactuation of the retractable support assembly 24 by ball chain 48.Immediately after such retracting operation begins the assembly 24 andmilker unit will be raised to a predetermined vertical position by theengagement of bracket 54 with catch bar 90. Such raising of the milkerunit during its retraction from underneath the cow will tend to preventthe detached teat cups from falling down onto the ground area at thestall.

After the detacher mechanism has been operated as described above, thesolenoid valve 94 is again deenergized by the operator to cause airunder pressure to be directed through air hose 44 to the upper end ofcylinder 40 to thereby return the piston (and piston rod) to theposition shown in FIGS. 2 and 3. The deenergization of solenoid willalso connect the sealed chamber 121 of milk valve 96 to exhaust therebycausing the milk valve to open. The mechanism is now ready for beginningthe milking cycle again.

I claim: .[.1. A milking unit support and detacher mechanism comprising:.[.3. A milking unit according to claim 1 in which said retract meansfurther includes first and second pulleys, said first pulley mounted atthe lower end of said main support column and said second pulley mountedon the end of the piston rod of said power cylinder, with said flexibleretract member extending from said retractable milking unit supportassembly downwardly and around said first pulley and then upwardly andaround said second pulley..]. .[.4. A milking unit according to claim 1in which said retract means further includes a counterweight assemblyfor said milker support column, said counterweight assembly adapted tosupport said milker support column in a substantially stable, verticalposition so that it can be moved vertically either up or down with onlya small amount of force applied to it..]. .[.5. A milking unit accordingto claim 4 in which said counterweight assembly is comprised of a cablefastened at one end to the upper end of said milker unit support columnand at the other end to a counterweight member, said counterweightmember mounted for slidable movement inside the upper portion of saidmilker support column, said counterweight assembly further including apulley member mounted on the top portion of said main support columnover which said cable member is wound..]. .[.6. A milking unit supportand detacher mechanism comprising:a main support column; a verticallymovable milker support column slidably mounted on said main supportcolumn; a horizontally extending retractable milking unit supportassembly mounted on said milker support column, said retractable milkerunit support assembly adapted to support a milker unit on the outer endthereof when the milker unit is attached to a cow for milking, saidmilker unit support assembly further adapted to be retracted from itsextended position underneath the cow to a retracted position adjacentthe cow; a flexible retract member fastened at one end to saidretractable milking unit support assembly; retract means for pulling onsaid flexible retract member to cause said milker unit support assemblyto be moved from its extended position to its retracted position, saidretract means including a power cylinder having a movable piston rodmounted on said main support column, said power cylinder beingoperatively connected to said flexible retract member and to said milkersupport column, said power cylinder adapted when energized in itsretract direction to pull on said flexible retract member and to alsomove said milker support column upwardly in a vertical direction; andcontrol means for automatically initiating the actuation of said powercylinder at a predetermined point in the milking cycle..]. .[.7. Amilking unit according to claim 6 in which said control means includes acontrol valve means and a milk valve means, said control valve meansadapted to control the operation of said power cylinder and said milkvalve means wherein when said power cylinder is energized for movementin the retract direction, the milk valve means will close to shut offflow of milk from the milker unit attached to the cow..]. .[.8. Amilking unit according to claim 7 in which said control valve means isfurther adapted when said power cylinder is energized in its returndirection to open said milk valve means..]. .[.9. A milking unitaccording to claim 8 in which said milk valve means includes an inletand an outlet adapted for connection to a milk line and a tubular valvemember of flexible material through which milk flows from said inlet tosaid outlet when said tubular valve member is in its normal unflexedposition, said milk valve means further including a pressurizing meansfor pressurizing the exterior surface of said tubular valve member tothereby cause said valve member to be flexed inwardly to cut off flow ofmilk therethrough..].
 10. A milking unit according to claim .[.9.]..Iadd.17 .Iaddend.in which said pressurizing means includes a sealedchamber in which said tubular valve member is mounted and a source ofair under pressure connected to said sealed chamber.
 11. A milking unitaccording to claim 10 in which said control valve means is operative toconnect said source of air under pressure with said sealed chamber ofsaid milk valve means when said power cylinder is energized in itsretract direction. .[.12. A milking unit according to claim 6 in whichsaid retract means further includes first and second pulleys, said firstpulley mounted at the lower end of said main support column and saidsecond pulley mounted on the end of the piston rod of said powercylinder, with said flexible retract member fastened at its other end tosaid main support column and then extracted upwardly and around saidsecond pulley and then downwardly from said second pulley and aroundsaid first pulley and then upwardly from said first pulley forconnection to said horizontally extending retractable milking unitsupport assembly..]. .[.13. A milking unit according to claim 6 in whichsaid retract means further includes a counterweight assembly for saidmilker support column, said counterweight assembly adapted to supportsaid milker support column in a substantially stable vertical positionso that it can be moved vertically either up or down with only a smallamount of force applied to it..]. .[.14. A milking unit according toclaim 13 in which said counterweight assembly is comprised of a cablefastened at one end to the upper end of said milker unit support columnand at the other end to a counterweight member, said counterweightmember mounted for slidable movement inside the upper portion of saidmilker support column, said counterweight assembly further including apulley member rotatably mounted on the top portion of said main supportcolumn over which said cable member is wound..]. .Iadd.
 15. A milkingunit support and detacher mechanism comprising:a main support column; avertically movable milker support column slidably mounted on said mainsupport column; a horizontally extending retractable milking unitsupport assembly mounted on said milker support column, said retractablemilker unit support assembly adapted to support a milker unit on theouter end thereof when the milker unit is attached to a cow for milking,said milker unit support assembly further adapted to be retracted fromits extended position underneath the cow to a retracted positionadjacent the cow; a flexible retract member fastened at one end to saidretractable milking unit support assembly; and retract means for pullingon said flexible retract member to cause said milker unit supportassembly to be moved from its extended position to its retractedposition, said retract means including a power cylinder having a movablepiston rod mounted on said main support column, said power cylinderbeing operatively connected to said flexible retract member and to saidmilker support column, said power cylinder adapted when energized in itsretract direction to pull on said flexible retract member and to alsomove said milker support column upwardly in a vertical direction, saidretract means further including first and second pulleys, said firstpulley mounted at the lower end of said main support column and saidsecond pulley mounted on the end of the piston rod of said powercylinder, with said flexible retract member extending from saidretractable milking unit support assembly downwardly and around saidfirst pulley and then upwardly and around said second pulley and thenanchored. .Iaddend..Iadd.
 6. A milking unit support and detachermechanism comprising:a main support column; a vertically movable milkersupport column slidably mounted on said main support column; ahorizontally extending retractable milking unit support assembly mountedon said milker support column, said retractable milker unit supportassembly adapted to support a milker unit on the outer end thereof whenthe milker unit is attached to a cow for milking, said milker unitsupport assembly further adapted to be retracted from its extendedposition underneath the cow to a retracted position adjacent the cow; aflexible retract member fastened to one end to said retractable milkingunit support assembly; retract means for pulling on said flexibleretract member to cause said milker unit support assembly to be movedfrom its extended position to its retracted position, said retract meansincluding a power cylinder having a movable piston rod mounted on saidmain support column, said power cylinder being operatively connected tosaid flexible retract member and to said milker support column, saidpower cylinder adapted when energized in its retract direction to pullon said flexible retract member and to also move said milker supportcolumn upwardly in a vertical direction; and control means forautomatically initiating the actuation of said power cylinder at apredetermined point in the milking cycle, said control means furtherincluding a control valve means and a milk valve means, said controlvalve means adapted to control the operation of said power cylinder andsaid milk valve means wherein when said power cylinder is energized formovement in the retract direction, the milk valve means will close toshut off flow of milk from the milker unit attached to the cow, saidcontrol valve means further adapted when said power cylinder isenergized in its return direction to open said milk valve means..Iaddend..Iadd.
 17. A milking unit support and detacher mechanismcomprising: a main support column; a vertically movable milker supportcolumn slidably mounted on said main support column; a horizontallyextending retractable milking unit support assembly mounted on saidmilker support column, said retractable milker unit support assemblyadapted to support a milker unit on the outer end thereof when themilker unit is attached to a cow for milking, said milker unit supportassembly further adapted to be retracted from its extended positionunderneath the cow to a retracted position adjacent the cow; a flexibleretract member fastened at one end to said retractable milking unitsupport assembly; retract means for pulling on said flexible retractmember to cause said milker unit support assembly to be moved from itsextended position to its retracted position, said retract meansincluding a power cylinder having a movable piston rod mounted on saidmain support column, said power cylinder being operatively connected tosaid flexible retract member and to said milker support column, saidpower cylinder adapted when energized in its retract direction to pullon said flexible retract member and to also move said milker supportcolumn upwardly in a vertical direction; and control means forautomatically initiating the actuation of said power cylinder at apredetermined point in the milking cycle, said control means furtherincluding a control valve means and a milk valve means, said controlvalve means adapted to control the operation of said power cylinder andsaid milk valve means wherein when said power cylinder is energized formovement in the retract direction, the milk valve means will close toshut off flow of milk from the milker unit attached to the cow, saidcontrol valve means further adapted when said power cylinder isenergized in its return direction to open said milk valve means, saidmilk valve means further including an inlet and an outlet adapted forconnection to a milk line and a tubular valve member of flexiblematerial through which milk flows from said inlet to said outlet whensaid tubular valve member is in its normal unflexed position..Iaddend..Iadd.
 18. A milking unit support and detacher mechanismcomprising:a main support column; a vertically movable milker supportcolumn slidably mounted on said main support column; a horizontallyextending retractable milking unit support assembly mounted on saidmilker support column, said retractable milker unt support assemblyadapted to support a milker unit on the outer end thereof when themilker unit is attached to a cow for milking, said milker unit supportassembly further adapted to be retracted from its extended positionunderneath the cow to a retracted position adjacent the cow; a flexibleretract member fastened to one end to said retractable milking unitsupport assembly; retract means for pulling on said flexible retractmember to cause said milker unit support assembly to be moved from itsextended position to its retracted position, said retract meansincluding a power cylinder having a movable piston rod mounted on saidmain support column, said power cylinder being operatively connected tosaid flexible retract member and to said milker support column, saidpower cylinder adapted when energized in its retract direction to pullon said flexible retract member and to also move said milker supportcolumn upwardly in a vertical direction, said retract means furtherincluding first and second pulleys, said first pulley mounted at thelower end of said main support column and said second pulley mounted onthe end of the piston rod of said power cylinder, with said flexibleretract member fastened at its other end to said main support column andthen extended upwardly and around said second pulley and then downwardlyfrom said second pulley and around said first pulley and then upwardlyfrom said first pulley for connection to said horizontally extendingretractable milking unit support assembly; and control means forautomatically initiating the actuation of said power cylinder at apredetermined point in the milking cycle. .Iaddend..Iadd.
 19. A milkingunit support and detacher mechanism comprising: a main support column; avertically movable milker support column slidably mounted on said mainsupport column; a horizontally extending retractable milking unitsupport assembly mounted on said milker support column, said retractablemilker unit support assembly adapted to support a milker unit on theouter end thereof when the milker unit is attached to a cow for milking,said milker unit support assembly further adapted to be retracted fromits extended position underneath the cow to a retracted positionadjacent the cow; a flexible retract member fastened at one end to saidretractable milking unit support assembly; retract means for pulling onsaid flexible retract member to cause said milker unit support assemblyto be moved from its extended position to its retracted position, saidretract means including a power cylinder having a movable piston rodmounted on said main support column, said power cylinder beingoperatively connected to said flexible retract member and to said milkersupport column, said power cylinder adapted when energized in itsretract direction to pull on said flexible retract member and to alsomove said milker support column upwardly in a vertical direction, saidretract means further including a counterweight assembly for said milkersupport column, said counterweight assembly adapted to support saidmilker support column in a substantially stable, vertical position sothat it can be moved vertically either up or down with only a smallamount of force applied to it. .Iaddend. .Iadd.
 20. A milking unitaccording to claim 19 in which said counterweight assembly is comprisedof a cable fastened at one end to the upper end of said milker unitsupport column and at the other end to a counterweight member, saidcounterweight member mounted for slidable movement inside the housingfor said milker unit support column, said counterweight assembly furtherincluding a pulley member rotatable mounted on the top portion of mainsupport column over which said cable member is wound. .Iaddend..Iadd.21. A milking unit support and detacher mechanism comprising: a mainsupport column; a vertically movable milker support column slidablymounted on said main support colunn; a horizontally extendingretractable milking unit support assembly mounted on said milker supportcolumn, said retractable milker unit support assembly adapted to supporta milker unit on the outer end thereof when the milker unit is attachedto a cow for milking, said milker unit support assembly further adaptedto be retracted from its extended position underneath the cow to aretracted position adjacent the cow; a flexible retract member fastenedat one end to said retractable milking unit support assembly; andretract means for pulling on said flexible retract member to cause saidmilker unit support assembly to be moved from its extended position toits retracted position, said retract means including a power cylinderhaving a movable piston rod mounted on said main support column, saidpower cylinder being operatively connected to said flexible retractmember and to said milker support column, said power cylinder adaptedwhen energized in its retract direction to pull on said flexible retractmember and to also move said milker support column upwardly in avertical direction, said retract means further including a pair ofpulleys, one of said pulleys mounted at the lower end of said mainsupport column and the other of said pulleys mounted on the end of thepiston rod of said power cylinder, with said flexible retract memberfastened at its other end to one of said pulleys and extending therefromto the other of said pulleys and around said other pulley and back tothe pulley at which the retract member is fastened and then around saidpulley to said retractable milking unit support assembly, said retractmeans further including a counterweight assembly for said milker supportcolumn, said counterweight assembly adapted to support said milkersupport column in a substantially stable, vertical position so that itcan be moved vertically either up or down with only a small amount offorce applied to it. .Iaddend..Iadd.
 22. A milking unit according toclaim 21 in which said control means includes a control valve means anda milk valve means, said control valve means adapted to control theoperation of said power cylinder and said milk valve means wherein whensaid power cylinder is energized for movement in the retract direction,the milk valve means will close to shut off flow of milk from the milkerunit attached to the cow. .Iaddend..Iadd.
 23. A milking unit accordingto claim 22 in which said control valve means is further adapted whensaid power cylinder is energized in its return direction to open saidmilk valve means. .Iaddend..Iadd.
 24. A milking unit according to claim23 in which said milk valve means includes an inlet and an outletadapted for connection to a milk line and a tubular valve member offlexible material through which milk flows from said inlet to saidoutlet when said tubular valve member is in its normal unflexedposition, said milk valve means further including a pressurizing meansfor pressurizing the exterior surface of said tubular valve member tothereby cause said valve member to be flexed inwardly to cut off flow ofmilk therethrough.